Apparatus for bridge construction



March 19, 1963 J. P. MURPHY 3,081,533

APPARATUS FOR BRIDGE CONSTRUCTION Original Filed Jan. 23. 1956ssneets-sheet 1 Joy/v Pfl/1 /p Mam/w March 19, 1963 J. P. MURPHY3,081,533

APPARATUS FOR BRIDGE CONSTRUCTION Original Filed Jan. 23, 1956 5Sheets-Sheet 2 IN VEN TOR. .J/M/ 0H/up M URPHY March 19, 1963 J..P.MURPHY APPARATUS Foa BRIDGE CONSTRUCTION original Filed. Jan. 2s, 195e 5Sheets-Sheet` 3 March 19, 1963 J. P. MURPHY APPARATUS FOR BRIDGECONSTRUCTION Original Filed Jan. 23, 1956 5 Sheets-SheerI 4 March 19,1963 J. P. MURPHY APPARATUS FOR BRIDGE CONSTRUCTION Original Filed Jan.23. 1956 5 Sheets-Sheet 5 v l A Q .mmm

www IMI W [IWI iwf l mi l United States Patent O 3,081,533 APPARATUS EURBRIDGE CGNSTRUCTIGN .Iolm Philip Murphy, Piedmont, Calif., assigner toYuba uConsolidated Industries, Inc., Emeryville, Calif., a corporationof Delaware riginal application Jan. 23, 1956, Ser. No. 560,678, nowPatent No. 2,958,949, dated Nov. 3, 1960. Divided and this applicationDec. 31, 1959, Ser. No. 3,222

3 Ciaims. (El. 29-252) This invention relates generally to apparatus forbridge construction and more particularly to apparatus vfor assemblingand erecting eyebar assemblies in bridges of the cantilever type.

The present application is Ia division of my co-pending parentapplication Serial No. 560,678, tiled January 23, 1956, now Patent No.2,958,940.

In cantilever bridges or spans it is often common practice for upperchord members that are in tension to be made up of a plurality `oflaterally spaced eyebars to form a laminated type of construction.Heretofore, the eyebars have been put in place one by one. This methodof assembling the eyebars has been found to be particularly ditlicultbecause of the great length and extreme exibility of the individualeyebars. The weight of the individual eyebars also makes them diicult tohandle. It also has been found that the eyes in the eyebars arefrequently out of alignment making it dicult to force the pins throughthe eyebars. This is particularly disadvantageous because the pinconnections must be made at a `considerable distance above the waterwithin a limited working area, and with a minimum oi equipment.

In general, it is an object of the present invention to provideapparatus for bridge construction in which the eyebars are readilyassembled into eyebar assemblies prior to eld erection and the completedeyebar assemblies placed in position in the cantilever span to eliminatethe aforementioned diiculties.

Another object of the invention is to provide apparatus for bridgeconstruction of the above character in which individual eyebars 'arespaced laterally from each other as they are assembled into clusters toform eyebar assemblies for the cantilever span and then alignedvertically and longitudinally by the use of expanding mandrels.

Another object of the present invention is to provide apparatus forbridge construction of the above character in which the assembledeyebars are bound together to form a unitary assembly after they havebeen aligned.

Another object of the invention is to provide apparatus for bridgeconstruction of the above character in which the eyebar assembly islifted into position and the pins driven by the use lof a jack.

Another object of the invention is to provide apparatus for bridgeconstruction of the above character in which the free end of the eyebarassembly is supported by tying it to the erected portion of the bridgespan to permit erection of the other truss members adjacent the free endof the eyebar assembly.

Another object of the invention is to provide apparatus for bridgeconstruction `of the type in which means is provided for assembling theeyebars into eyebar assemblies to provide tension members for cantileverspans.

Another object of the invention is to provide apparatus for bridgeconstruction of the above character in which means is provided forspacing the eyebars in each eyebar assembly and roughly .aligning theeyebars.

Another object of the invention is to provide apparatus for bridgeconstruction of the above character in which an expanding mandrel isused for accurately aligning the eyebars vertically and longitudinally.

A further object of the invention is to provide apparatus vfor bridgeconstruction of the above character in 3,081,533 Patentes Mar. is, reesice which a platform is provided for supporting men, apparatus and theconnecting pin while it is being driven into place by jacking.

A still further object of the invention is to provide .apparatus forbridge construction of the above character in which a cable assembly isprovided for supporting the free end of the eyebar assembly after oneend of the eyebar assembly has been connected to the cantilever span topermit the erection of subsequent members in the cantilever spanpreparatory to fastening the free end of the eyebar assembly. l

Additional objects and features of the invention will appear from thefollowing description in lwhich the preferred embodiment has been setforth in detail in conjunction with the accompanying drawing.

Referring to the drawing:

FIGURE 1 is an elevational view of a typical cantilever span after ithas been completed.

FIGURE 2 is an enlarged side elevational view showing the progressiveerection of the `anchor arm and the cantilever arm of the cantileverspan from one of the bridge piers by the balanced cantilever erectionmethod.

FIGURE 3 is a plan view of the cantilever span shown in FIGURE 2.

FIGURE 4 is an enlarged cross sectional view taken along the line 4-4 ofFIGURE 2.

FIGURE 5 is a cross sectional view taken along the line 5 5 of FIGURE 4.

FIGURE 6 is la reduced partial plan view of the pin connection shown inFIGURE 5 but showing the pin in its nal position.

FIGURE 7 is an enlarged cross sectional View taken along the line 7-7 ofFIGURE 5.

FIGURE 8 is a partial view of the pin with a permanent cap.

FIGURE 9 is a side elevational view of a typical eyebar assembly in theassembly yard or area.

FIGURE 10 is a plan view of the eyebar assembly shown in FIGURE 9.

FIGURE 11 is an enlarged fragmentary side elevational view of the eyebarsupports.

FIGURE 12 is an enlarged cross sectional view taken along the line 12-12of FIGURE 9 and shows the eyebar supports.

FIGURE 13 is an enlarged cross sectional view taken along the line13--13 of FIGURE 9 and shows the mandrel in place but before it has beenexpanded.

FIGURE 14 is a partial cross sectional view similar to FIGURE 13 butshowing the mandrel in a fully expanded position.

FIGURE 15 is a side elevational view taken along the line 15-15 ofFIGURE 13.

FIGURE 16 is a cross sectional view line 1%*16 of FIGURE 13.

FIGURE 17 is a cross sectional view taken along the line 17-17 of FIGUREV9 and shows a tightening and spaciriy assembly.

FIGURE 18 is a cross sectional view taken along the line 11d-18 ofFIGURE 9 and shows the lifting assembly.

The method and apparatus I have used for the placement of eyebars incantilever bridge spans can best be understood by iirst giving a typicalerection sequence Lfor a `cantilever span. One method commonly used forerecting a cantilever span and `often referred 'to as the BalancedCantilever Erection Method is shown in FIG- URES l, 2 and 3 of thedrawing. By this method an 4inclined shorting strut 1li is erectedadjacent the tower portion 12 of a pier 13. The initial bottom door andchord system including a plumb post 1'4 is then erected. Stili' leg`travelers 16 and 17 are mounted in the completed portion and are usedfor completing the anchor arm -IEI and cantilever arm 19 by balancingone arm taken along the against the other as is well known to those`skilled in the art. The same procedure is used for erecting anchor andcantilever .arms yfrom the next pier. Both cantilever arms are :then`completed to close the span. Temporary shoring bents 121 may be used tosupport the anchor `arms when fthe span between pier-s is great.

The aforementioned method of :erection of cantilever spans issubstantially conventional and hence is not 'given in detail. Myinvention is 'concerned primarily with the method and apparatus forassembling and erecting `the eyebar assemblies 23 which `form the upperchord members in the `anchor and the cantilever arms. Even though thegeneral method of erecting the cantilever span iS changed theinstallation of the eyebar `a-sserrrblies will remain :the same.V

In accordance with my invention, I mount a plurality of elongate eyebarsZ7 having eyes 23 at each end fupon a suitable :framework 29 such asshown in FIGURE l0. The framework lconsists of a pair of lbeams 3dresting upona relatively flat s-unface 31 as in an assembly yar-d orarea. A pair of shorter I-beam-s 32 and 33 are mounted at right anglesto and near the ends of Iebeams Sti and serve to carry a plurality ofeyebar supports 34.

Each of the eyebar supports 34 consists of a pair of flat plate likemembers 36 xed to a pair of right angle members 37 to form asubstantially U-shaped assembly. Each of the right angle members isprovided with suit-able clamping means such as a bolt 3S and a pair ofnuts 39 for locking the eyebar supports 34 in posi-tion on the flanges4d of the l-.beams 32 or 33.

The right angle members 37 are fastened tto the plate like members 36 insuch a manner that the toe portions 42 are level and in alignment whenthe eyebar supports 34s are mounted upon the I-beams 32 and '33.

The eyebar supports 34 are mounted upon the I-beams 32 and 33 in apredetermined space relationship and the eyebars l27 are laid side byside in the eyebar supports 34 in a manner shown in FIGURE 10. One endof each of the eyebars -is mounted ush against a backstop i3 which isfixed `to one end of the channel members 29. This serves to roughlyalign the eyebars in a longitudinal direction.

After the eyebars have been mounted in the eyebar supports 34 ashereinbefore described, a plurality of tightening and spacing assemblies46 are spaced longitudinally along the length of the assembled eyebars27. However, the tightening `and spacing assemblies are not tightened atthis time. A typical tightening and spacing assembly 46 is shown inFIGURE 18 and consists of a plurality of spacing plates 47 of differentwidths and a plurality of spacing members 48 mounted upon a pair ofelongate bolts y49 and 511.

Each of the spacing members 4S consists of a pair of vertical plate likemembers 52 land 53 and a pair of horizontal bracing members S4 and 56connecting the opposite ends of the plate like members. A U-shaped rod57 is connected to the upper ends of the plate like members 52 and 53for a purpose hereinafter described.

IIn placing the .tightening and spacing assemblies 46 'upon the eyebarassembly, the spacing plates 47 and the spacing members 48 are iirstmounted upon the upper elongate bolt 49 after which the spacing plates47 and the spacing members 48 are dropped down into the spaces betweenthe eyebars and then the lower bolt 51 is inserted. By utilizingdifferent Widths of spacing plates 47 it is possible to properly spacethe eyebars.

Suitable means is provided for lifting the eyebar assembly and consistsIof a lifting beam assembly 59 mounted midway between the ends of theeyebar assembly. Such a lifting beam assembly consists of a pair ofhorizontal channel members 61 and 62. which are connected to a .pair ofvertical lifting members 63 and 64, the upper ends of the same beingprovided with openings 66 for the recetpion of hooks or the like. A pairof bolts 67 and 68 serve to secure the vertical lifting members 63 and64 d to the eyebar assembly. A plurality of spacing plates 47 of variouswidths are mounted upon the bolts 67 `and 68 and :servie as spacingmeans in a manner simi-lar t0 that in the tightening land spacingassemblies d6.

A plurality of angular members 71 are spaced longitudinally of theeyebar assembly 23 and are lfastened t0 the eyebars by clamps 72.. Theangular members 'il .form a permanent part of the cantilever span andserve as a support for a handrail (not shown).

After .the tightening and spacing assemblies 46 and the lifting beamassembly 59 are in place, the eyes 28 in the eyebar assembly are readyfor alignment.

It is well known to those skilled in the art of bridge building that inmaking eyebars it is practically impossible to maintain exacttolerances. If the eyes 28 in the eyebars are out of alignment it willbe difficult to make the pin connection for connecting the eyebarassembly to the other bridge members. Therefore, I have found itdesirable to align the eyes in each eyebar assembly before the assemblyis lifted into place. To accomplish this I have provided expandingmandrels or pilot pin assemblies 77 which are adapted to be inserted inthe eyes 28 of the eyebar assembly.

Each pilot pin assembly 77 con-sists of a suitable nurnber of segmentssuch as the four segments 78 shown in FIGURES 16 and 17. Each segmentcomprises an arcuate portion 79 and a pair o-f plate like portions S1and e2. The plate like portions 81 and S2 are fixed to the arcuateportion 79 and extend radially therefrom to subtend an arc of degrees. Aplurality of .reinforcing portions 183 are fixed to the arcuate portion79 and are spaced longitudinally along the length thereof. A beveled endportion 814 is fixed to the reinforcing portions 83 adjacent theopposite ends of the arcuate portion 79. Additional arcuate reinforcingportions 86 serve to connect the outer ends of the plate like portions81 and 82 and are also `fixed to the outer periphery of the arcuatereinforcing port-ions 83.

The segments 78 are connected into a cylindrical eX- -panding-typemandrel by a plurality of bolts 87 mounted lin holes 8S in the platelike portions 811 and 82. The inner ysurfaces of the arcuate portions 79are provided with a pair of abutment members or shoulders 89. A U-bolt91 is mounted in each end of each of the segments 78. The U-bolts areused for facilita-ting withdrawal of the pilot pin assembly 77 from theeyes 2.8.

A hollow pipe-like member 93 is loosely mounted within the opening 94formed by the arcuate portions 79. It is provided with a pair ofenlarged tapered portions 96 and 97 for a purpose hereinafter described.A draw lbar 9S is slidably mounted within the hollow pipe-like member 93and is provided with a plurality of annular grooves 99 spacedlongitudinally thereof. The draw bar 98 is of a length that it extendssubstantially beyond both ends of the pipe-like member 93. A clamp oryoke 101 is mounted in one of the grooves 99 at one end of the draw bar.Suitable shimming means Isuch as a pipe section 102 is mounted on thedraw bar and takes up substantially all of the play between the yoke 101and the adjacent end of the hollow pipe-like member 93.

Suitable means is mounted on the other end of the draw bar 98 `forapplying a pulling force to the draw bar. One means found to besatisfactory consists of hydraulic ram 104 such as R60l0 rammanufactured by Templeton, Kenly & Company of 16th and Gardner Road,Broadview, Illinois. The ram 104 is connected to a suitable fluid pump(not shown) by means of hydraulic lines 106 and 107. A yoke 108 similarto that shown in FIGURE 16 is mounted in one of the grooves 99 in theother end of the draw bar 93 adjacent the upper end of the ram 104. Adrive washer 109 is mounted on the draw bar 98 between the ram 104 andthe pilot pin assembly 77.

Assuming that the bolts 87 are so adjusted that Ithe segments 78 `can beexpanded, the ram 104 may be operated to apply pulling force to the drawbar 98. This will cause movement of the draw bar to the right as shownin FIG- URE 14 to cause ythe enlarged tapered portions 97 of the hollowpipe-like member to move into engagement with the abutment members orshoulders 89 on the segment 78. This will cause the segments 78 to beexpanded symmetrically in a radial direction to cause alignment of theeyes 23 in the eyebars by movement of the eyebars vertically andlongitudinally, Movement of the draw bar is continued until the Alargestportion of the enlarged tapered portion 97 engages the shoulders 89 asshown in FGURE l5. Both of the pilot pin assemblies 77 are operatedsimultaneously so that the eyes on both ends of the eyebar assembly arealigned.

As soon as the pilot pin assemblies 77 have been moved to the fullyexpanded position, the tightening and spacing assemblies 46 are securedto maintain the eyebars in alignment. If desired, the pilot pin assembly77 may be removed by operating the ram 11M- lto cause it to continue topull the hollow pipe-like member towards the ram until the enlargedtapered portions 97 no longer engage the shoulders 89. The pilot pinassemblies may then be readily removed by grasping the U-bolts 91 anddrawing the assemblies from the eyes 28.

Normally, however only one of the pilot pin assemblies is removed inIthe yard and the other pilot pin assembly is not removed until a pin isdriven in the other end as hereinafter described.

After the eyebars 27 have been assembled into eyebar assemblies 23 andaligned as hereinbefore descri-bed they are loaded on suitable meanssuch as a barge 111 and moved to the erection site.

- Let is be assumed that the erection of the cantilever span hasprogressed to the point shown in FIGURE 3 and that the vertical trussmember 112 and the last erected eyebar assembly 23, which will bedesignated as 113, are in the position shown. The following procedure isused Vfor making the pin connection with the next eyebar assembly 23 tobe erected, which will be designated as 114, and the vertical trussmember 112 and the eyebar assembly 113. A suitable platform 116 isconnected to the upper portion of the vertical truss member 112.

The platform 116 consists essentially of a bottom platform member 117connected to truss member 112. A plurality of vertical mem-bers 118 andbracing members 119 are connected to the bottom platform member 117 andto a channel shaped member 121 which serves as a working surface for thepin 122 and the ram 123. A block 124 resting upon the member 121supports the ram in a position to drive the pin 122". A plurality ofrods 125 are mounted along the outer edges of the bottom platform member117V and form a rectangular enclosure to serve as safety or guide railsfor the platform.

The eyebar assembly 114,V is lifted from the barge 111 by suitable meanssuch as the stiff leg derrick 16 which is connected to the lifting beamassembly 59. The eyebar assembly 114 is then held in the position shownin Pif- URE 2 so that one end is adjacent the upper end of truss member112 `and the free end of eyebar assembly 113.

The upper end of the vertical truss member 112 is provided with `aninclined bottom gusset plate 131. A pair of side gusset plates 132 and133 are fixed to the gusset plate 131 and are provided with a bore 134which is adapted to receive pin 122.

A pair of temporary erection supports 137 and 13S are.

mounted upon the bottom gusset plate 131 and serve as temporary supportsfor the adjacent ends of the eyebar assemblies 113 and 114. The erectionsupports 137 `and 133 consist essentially of a prefabricated beam 139 inwhich the upper surface 141 is inclined with respect to the otherportions of the beam. The beam is connected to a plate 142 which isfastened by means of a hook bolt 143 to a channel member144 secured tothe bottom gusset plate 131. A plurality of wooden Wedges 146 (FIG- URES5 and 7) are used for carrying `the individual eyebars of the eyebarassembly upon the temporary erect-ion supports 137 and 138.

In making the pin connection between the vertical truss member 112 andthe eyebar assemblies 113 and 1111, the free end of the eyebar assembly113 is lowered into place on `top of the wedges 146 resting on thetemporary erection support 137 and upon wedges 147 immediately below thefree end of the eye-bar assembly 113. The eyebar assembly 114i islowered into position so that the eyebars of assemblies 113 and 114 areinterleaved as shown in FlGURE 5 and eyebar assembly 114 is resting uponthe temporary erection support 133 and wedges 147.

If required, an additional stilfener plate: 148 (FIGURE 7) may beinserted for strengthening the bottom gusset plate 131 to carry theweight of the eyebar assemblies 113 and 114 after they have been set inplace but before they have been pinned to the side gusset plates 132 and133.

The position of the wedges 146 and 147 can be shifted to roughly alignthe eyes in the eyebar assemblies 113 and 114 Iwith the bore 134 in theside gusset plates 132 and 133. The pin 122 is lifted and placed uponthe channel shaped member 121 on the platform 116. The pin 122 isprovided with a bore 151 which is adapted to receive the draw bar 152having a plurality of grooves 153 spaced longitudinal-ly along thelength thereof. A pilot nut 154 with rounded corners is threaded on oneend of the pin 122 and facilitates initial insertion of the pin -122into bore 131i. The draw -bar 152 extends substantially beyond each endof the pin 122 and extends through a member 156. A yoke or keeper 157engages one of the grooves `153 in the draw bar 152 and serves toprevent the draw bar from being pulled through the member 156i. Themember is provided with a plurality of legs 158 which serve to space themember 156 from the adjacent eyebar to provide a space which is adaptedto receive the pilot nut 154 when the pin 122 is drawn to its finalposition.

The ram 123 is `then mounted upon the draw bar 152 adjacent a drive nut161 and is held in place by a yoke or keeper 162 engaging a groove 153in the draw bar. The ram 123 is identical to ram 104 hereinbeforedescribed and is operated by a suitable tiuid pump (not shown).`Operation of the pump causes movement of 4the ram plunger 163 to theright to cause the ram 123 to pull against the draw bar `1512 to pushthe pin 1212 into the bore 134 and eyes 2S. If desired, the lpin 122 maybe greased to facilita-te driving of :the pin 122. Since the stroke ofthe ram plunger is limited, it is necessary to drive lthe pin 122 insteps, the yoke 1612 being moved to engage the next successive grooveuntil the pin `122 is driven into place. lBecause the eyes in theeyebars have .been previously aligned as hereinbefore described, the pin122 is driven into place with little or no difficulty. After the pin 122is in place, lthe ram 123 `and the draw bar 1'52 and the member i156 areremoved. The pilot nut 1154 is also removed from the pin and a permanentcap 164 (FIG- URE 8) is put into place. A similar cap 165 is placed onthe other end of the pin (FGURE 6) to complete the pin connectionbetween the vertical ltruss member 112 and the eyebar assemblies 113 and114.

.A top gusset plate 166 if such is provided in the design is thenriveted in place .and the lateral truss members 167 are riveted togusset extensions 168. The platform 1.16 may then be removed for use inmaking the next pin connection.

After the pin connection between the vertical truss member 112 and theeyebar assemblies 113 and 114 has been completed, the free end of theeyebar assembly 114 is tied to the completed portion of the anchor armin a manner similar to that shown in the cantilever arm in FIGURE 3 inwhich a suitable cable assembly 169 has one end connected 'to the freeend of an eyebar assembly 1711 and the other end connected to apreviously completed pin connection 172.

The free end of the eyebar assembly `114 is maintained in this tied-backposition While the additional truss members shown in dotted lines inFIGURE 5 are erected. As

soon as the vertical truss member represented by the dotted line 173 iserected, the free end of the eyebar assembly 1114 may be lowered to restupon the vertical truss member represented by the `dotted line 173. Thenext eyebar assembly may then be raised by the stiff leg derrick 16 andone end of the eyebar assembly pinned to the free end of the eyebarassembly 114 and the Ivertical truss member represented by the dottedlines 7.3, in a manner very similar to that hereinbefore described.

After both ends of the eyebar assembly 114 have been pinned, thetightening and spacing assemblies 4o may be loosened and removed bysuitable means. For example, they may be removed by a sling (not shown)connected to the stiff leg derrick 16 and by connecting the ends of thesling to the U-shaped rods 57 Vconnected to the spacing members 4S,

It is apparent that the eyebar assemblies for the cantilever arm may beerected in a manner similar to that described for erecting the eyebarassembly ,114 in the anchor arm. it is also apparent that the eyebarassemblies 23 previously erected in the anchor and cantileverarms priorto the erection `ot" eyebar assembly 114 are also erected in a similarmanner. For example, in commencing the erection of the cantilever span,the plumb post 14 is erected on the tower 13. After -a few of the othertruss members have been erected in a manner well known to those skilledin the art of bridge building, the eyebar assemblies 23 on each side ofthe plumb post 14 are lifted by the sti leg dericks 16 and 17, and oneof the ends of each of the eyebar assemblies connected to the plumb post14 in a manner hereinbefore described.

It is apparent from the foregoing that I have provided a new method andapparatus for erecting eyebar assemblies used in forming the uppertension chords in the anchor and cantilever arms of a ycantilever span.The use of pre-assembled and aligned eyebar assemblies greatlyfacilitates placement of the eyebar assemblies in the cantilever spanand makes possible a substantial saving in the cost of erection.

I claim:

1. Apparatus for :driving a pin connecting one of the ends of each pairof eyebar assemblies to a truss member in a cantilever span of the typewherein the eyes in the eyebar assemblies .are aligned with a bore inthe upper portion of said -truss member and are `adapted to receive saidpin `and wherein said pin has a central .bore extending therethrough,the apparatus comprising a platform adapted to be secured to the upperportion of said truss member, `supporting means mounted on said platformand adapted to carry said pin in a horizontal position substantially inalignment with the bore in said upper truss member and the eyes in saideyebar assemblies, a pilot nut having rounded corners adapted to bemounted on the end of said pin rst entering the bore in said trussmember to facilitate insertion of the pin, a draw bar adapted to beslidably mounted in the central bore in said pin and extendingsubstantially beyond both ends of said pin and through the bore in saidtruss member and the eyes in said eyebar assemblies, means for vsecuringyone end of said draw bar on one side of said eyebar assemblies, saidlast named means being adapted to accommodate said pilot nut ywhen saidpin is drawn into its iinal position, means connected to the other endof said draw bar and engaging said pin for applying a pulling force tosaid draw bar to thereby push said pin into the bore in the truss memberand the eyes in the eyebar assemblies, said means connected to the otherend of the drawbar and engaging said pin including a hydraulic ramhaving a predetermined stroke less than the distance through which thepin must travel, and means engaging the hydraulic ram to permit step bystep advancement of the pin.

2. Apparatus for driving a pin connecting one of the ends tof each pairof eyebar assemblies to a truss member in a cantilever span of the typewherein the eyes in the eyebar assemblies are aligned with a bore in theupper portion of said truss member and are adapted to receive said pin,and wherein said pin has a central bore extending therethrough, theapparatus comprising a platform adapted to be secured to the upperportion of said truss member, supporting means mounted on said platformand adapted to carry said pin in a horizontal position substantially inalignment with the lbore in said upper truss member and the eyes in saideyebar assemblies, a pilot nut adapted to be mounted on one end of saidpin iirst entering the bore in said truss member to facilitate insertionof the pin, a draw bar adapted to be slidably mounted in the centralbore in said pin and extending substantially beyond both ends of saidpin and through the bore in said truss member and the eyes in saideyebar assemblies, means for securing one end of said drawbar on oneside Of said eyebar assemblies, means connected to the other end of saiddraw bar `and engaging said pin for applying a pulling force to saiddraw bar to thereby push said pin into the bore in the truss member andthe eyes in the eyebar assemblies, said last named means including ahydraulic ram having a predetermined stroke less than the distancethrough which the pin must travel, and means engaging the draw bar andthe hydraulic lram on said draw bar to permit step-bystep advancement ofthe pin, each step being approximately equal to the stroke of the ram.

3, Apparatus as in claim 2 wherein said last named means comprises aplurality of grooves formed in said draw bar and spaced longitudinallythereof, and a yoke adapted to be mounted in a predetermined groove toengage the hydraulic ram.

References Cited in the file of this patent UNITED STATES PATENTS1,841,190 Iustiss Jan. 12, 1932 2,235,643 Pfauser Mar. 18, 19412,361,783 McLaughlin Oct. 31, 1944 2,430,201 Wyscaver Nov. 4, 19472,469,723 Greene May 10, 11949 2,509,305 Landis May 30, 1950 FOREIGNPATENTS 732,450 Germany Mar. 3, 1943 671,478 Great Britain May 7, 1952

1. APPARATUS FOR DRIVING A PIN CONNECTING ONE OF THE ENDS OF EACH PAIROF EYEBAR ASSEMBLIES TO A TRUSS MEMBER IN A CANTILEVER SPAN OF THE TYPEWHEREIN THE EYES IN THE EYEBAR ASSEMBLIES ARE ALIGNED WITH A BORE IN THEUPPER PORTION OF SAID TRUSS MEMBER AND ARE ADAPTED TO RECEIVE SAID PINAND WHEREIN SAID PIN HAS A CENTRAL BORE EXTENDING THERETHROUGH, THEAPPARATUS COMPRISING A PLATFORM ADAPTED TO BE SECURED TO THE UPPERPORTION OF SAID TRUSS MEMBER, SUPPORTING MEANS MOUNTED ON SAID PLATFORMAND ADAPTED TO CARRY SAID PIN IN A HORIZONTAL POSITION SUBSTANTIALLY INALIGNMENT WITH THE BORE IN SAID UPPER TRUSS MEMBER AND THE EYES IN SAIDEYEBAR ASSEMBLIES, A PILOT NUT HAVING ROUNDED CORNERS ADAPTED TO BEMOUNTED ON THE END OF SAID PIN FIRST ENTERING THE BORE IN SAID TRUSSMEMBER TO FACILITATE INSERTION OF THE PIN, A DRAW BAR ADAPTED TO BESLIDABLY MOUNTED IN THE CENTRAL BORE IN SAID PIN AND EXTENDINGSUBSTANTIALLY BEYOND BOTH ENDS OF SAID PIN AND THROUGH THE BORE IN SAIDTRUSS MEMBER AND THE EYES IN SAID EYEBAR ASSEMBLIES, MEANS FOR SECURINGONE END OF SAID DRAW BAR ON ONE SIDE OF SAID EYEBAR ASSEMBLIES, SAIDLAST NAMED MEANS BEING ADAPTED TO ACCOMMODATE SAID PILOT NUT WHEN SAIDPIN IS DRAWN INTO ITS FINAL POSITION, MEANS CONNECTED TO THE OTHER ENDOF SAID DRAW BAR AND ENGAGING SAID PIN FOR APPLYING A PULLING FORCE TOSAID DRAW BAR TO THEREBY PUSH SAID PIN INTO THE BORE IN THE TRUSS MEMBERAND THE EYES IN THE EYEBAR ASSEMBLIES, SAID MEANS CONNECTED TO THE OTHEREND OF THE DRAWBAR AND ENGAGING SAID PIN INCLUDING A HYDRAULIC RAMHAVING A PREDETERMINED STROKE LESS THAN THE DISTANCE THROUGH WHICH THEPIN MUST TRAVEL, AND MEANS ENGAGING THE HYDRAULIC RAM TO PERMIT STEP BYSTEP ADVANCEMENT OF THE PIN.